Panelized shadow box

ABSTRACT

In a method of supplying an element for covering a non-vision area in a curtain wall on an architectural structure, a plurality of shadow boxes is prefabricated at a location remote from both a unitized curtain wall assembly shop and the architectural structure. The shadow boxes are prefabricated by sealing an interior spacer between a vision glass panel and a back structure. The back structure includes an insulating material surrounded by a rigid envelope. The vision glass panel, the back structure and the interior spacer define a hermetically sealed void therein. A structural seal is applied about the interior spacer and is affixed to the peripheral edge of the vision glass, the interior spacer and the back structure. The plurality of shadow boxes is then delivered to a selected one of the unitized curtain wall assembly shop and the architectural site.

CROSS-REFERENCE TO RELATED APPLICATION(S)

This application is a divisional of and claims the benefit of U.S.patent application Ser. No. 14/162,984, filed on Jan. 24, 2014, nowissued as U.S. Pat. No. 9,243,442, which is a non-provisional of andclaims the benefit of U.S. Provisional Patent Application Ser. No.61/757,396, filed Jan. 28, 2013, the entirety of each which is herebyincorporated herein by reference.

BACKGROUND OF THE INVENTION

1. Field of the Invention

The present invention relates to architectural devices and, morespecifically, a shadow box for use in various building cladding systemsincluding but not limited to unitized and stick system curtain wall,window wall, strongback, punched windows and other framed assemblies andrain screen assemblies.

2. Description of the Related Art

A curtain wall is a non-structural outer covering of a building. Acurtain wall serves to provide a desired exterior appearance and to keepexterior environmental elements (e.g., wind, rain, etc.) out of thebuilding. While a curtain wall will impart horizontal forces, such aswind loading, to the structural elements of the building, it does notbear the vertical load of the building (except for its own dead weight).Because it is non-structural, it provides a relatively inexpensive wayto finish a building's exterior.

A typical enclosure system such as a curtain wall includes an array ofmullions, which are vertical and horizontal elements that holdtransparent vision glass and opaque spandrel zones. A typical spandrelzone can consist of the following components: a facing material (suchas, aluminum, stone, glass masonry, etc.), insulation, and an air andvapor barrier.

The requirements for thermal insulation and fire separation dictate theneed for opaque spandrel panels. In addition, other elements that arenot desired to be seen are typically concealed by a opaque panels thatcan be identical to the spandrel or made of other materials. One way tohide such elements is by substituting opaque glass over the elements tobe hidden. However, this approach interrupts the visual effect of thevision glass spandrels, which can be an aesthetically undesirableeffect.

To give the illusion of depth, some architects design curtain walls inwhich the elements to be hid are covered with shadow boxes. A shadow boxis a spandrel with a vision glass exterior and an opaque back that isoffset by several inches from the vision glass exterior. The opaque backhides the elements to be hidden, while the visual effect of the offsetcan appear similar to the vision glass glazing of the rest of thecurtain wall.

Some shadow boxes are deliberately vented to the exterior of thebuilding, some are inadvertently vented to the interior of the buildingand some are deliberately fully sealed. If they are vented to theexterior, it is possible for dust, insects and the like to enter theshadow box. It is also possible for condensation to form within theshadow box during hot and humid weather. If they are vented to theinterior there may be a pathway for dust to form on the inner (#2)surface of the glazing. During cold weather, there is also a highpossibility for condensation to form within the spandrel box. If theyare fully sealed and moisture enters the spandrel box, either throughfaults in the inner or outer seals, then long-term condensation mayoccur. Dust and dirt collection within a spandrel box, the presence ofinsects and the like within a spandrel box and the presence ofcondensation within a spandrel box can all be considered as failures ofthe spandrel box. Opening an installed shadow box to clean it is not apractical solution to problems involving dirt and moisture.

Another form of shadow box uses a conventional insulating glass unitwith a solid frit or coating on the innermost surface of the glass. Thissystem addresses the visual problems of the standard spandrel boxsolution described above by visually blocking any dirt, dust, insectsand the like, and condensation that may form in externally or internallyvented or fully sealed shadow boxes. This form of shadow box does notprovide the visual depth often desired by the designer. In addition,this form of shadow box may not prevent condensation formation (and itprevents the visual warning that condensation may be forming). Suchcondensation may lead to failures of the shadow box.

Cladding system like curtain walls can be constructed on-site (in whichcase they are referred to as “stick systems”) or they can be assembledin panels at a unitized assembly shop as part of unitized systems suchas unitized curtain walls that are shipped to the construction site. Inboth cases, shadow boxes are constructed as part of the construction ofthe panels of the curtain wall. This makes curtain wall construction atime consuming process. Also, since the shadow boxes are constructed onan ad hoc basis, ensuring that their seals and tolerances are suitablefor long duration construction can be difficult. Multiple decades of adhoc shadow box construction has demonstrated that it is hard to achievean effective hermetic seal into a shadow box made this way.Additionally, when constructing shadow boxes on-site and at unitizedassembly shops typically results in the introduction of dust and otherimpurities into the shadow box, which detracts from the visual effect ofthe shadow box.

Therefore, there is a need for a prefabricated shadow box unit thatemploys seals with a long lifetime.

SUMMARY OF THE INVENTION

The disadvantages of the prior art are overcome by the present inventionwhich, in one aspect, is a method of supplying an element for covering anon-vision area in a curtain wall on an architectural structure, inwhich a plurality of shadow boxes is prefabricated at a location remotefrom both a unitized curtain wall assembly shop and the architecturalstructure. The shadow boxes are prefabricated by sealing, with a firstairtight and moisture resistant hermetic seal and a second airtight andmoisture resistant hermetic seal, an interior spacer between visionglass panel and back structure, the spacer having a length so that thevision glass panel is spaced apart from the back structure, the backstructure including a first insulating material and a rigid envelopedisposed around the first insulating material, the spacer disposed alonga peripheral edge of the vision glass panel and along a peripheral edgeof the back structure so as to hold the vision glass panel in a spacedapart relationship from the back structure, so that the first hermeticseal seals the interior spacer to the vision glass panel and so that thesecond hermetic seal seals the interior spacer to the back structure andso that the vision glass panel, the back structure and the interiorspacer define a hermetically sealed void therein. A structural seal isapplied about the interior spacer and so as to be affixed to theperipheral edge of the vision glass, the interior spacer and the backstructure. The plurality of shadow boxes is then delivered to a selectedone of the unitized curtain wall assembly shop and the architecturalsite.

In another aspect, the invention is a curtain wall system for coveringan architectural structure that includes a frame structure that isconfigured to be affixed to an outer surface of the architecturalstructure. A plurality of vision glass panels are supported by the framestructure. A plurality of shadow boxes is prefabricated prior todelivery to both a unitized curtain wall assembly shop and thearchitectural structure. Each of the plurality of shadow boxes isconfigured to be affixed to the frame structure and configured to covera non-vision area of the architectural structure. Each of the pluralityof shadow boxes includes: a vision glass panel having a peripheral edge;a back structure, having a peripheral edge, the back structure includingan insulating material and a rigid envelope disposed around theinsulating material; an interior spacer disposed along the peripheraledge of the vision glass panel and along the peripheral edge of the backstructure so as to hold the vision glass panel in a spaced apartrelationship from the back structure, the interior spacer defining atleast one chamber therein into which a desiccant is disposed; a firsthermetic seal that seals the interior spacer to the vision glass paneland a second hermetic seal that seals the interior spacer to the backstructure so that he vision glass panel, the back structure and theinterior spacer define a hermetically sealed void therein; a structuralseal disposed about the interior spacer and affixed to the peripheraledge of the vision glass, the interior spacer and the back structure;and a back panel disposed within the hermetically sealed void andagainst the back structure, the back panel including an aesthetictreatment configured to present a desired visual effect to viewerslooking through the vision glass panel.

In yet another aspect, the invention is a shadow box for use with anarchitectural curtain wall system that includes a vision glass panelhaving an outside #1 surface, an opposite inside #2 surface and aperipheral edge. A back structure has a peripheral edge and includes afirst insulating material and a rigid envelope disposed around the firstinsulating material. An interior spacer defines a plurality of chamberstherein in which a desiccant is placed. The interior spacer is disposedalong the peripheral edge of the inside #2 surface of the vision glasspanel and along the peripheral edge of the back structure so as to holdthe vision glass panel in a spaced apart relationship from the backstructure. A first polyisobutylene seal seals the interior spacer to thevision glass panel and a second polyisobutylene seal seals the interiorspacer to the back structure so that the vision glass panel, the backstructure and the interior spacer define a hermetically sealed voidtherein. The spacer has a length so that the vision glass panel isspaced apart from the back structure by more than 1 inch. A siliconeseal is disposed about the interior spacer and is affixed to theperipheral edge of the vision glass, the interior spacer and the backstructure so as to provide structural support thereto. The shadow boxhas been prefabricated prior to insertion into a pre-assembled framestructure.

These and other aspects of the invention will become apparent from thefollowing description of the preferred embodiments taken in conjunctionwith the following drawings. As would be obvious to one skilled in theart, many variations and modifications of the invention may be effectedwithout departing from the spirit and scope of the novel concepts of thedisclosure.

BRIEF DESCRIPTION OF THE FIGURES OF THE DRAWINGS

FIG. 1A is a front elevational view of one embodiment of a shadow box.

FIG. 1B is a cross sectional view of the embodiment shown in FIG. 1A,taken along line 1B-1B.

FIG. 2 is a cross-sectional view of a corner of a second embodiment of ashadow box.

FIG. 3 is a cross-sectional view of a corner of a third embodiment of ashadow box.

FIG. 4 is a cross-sectional view of a corner of a fourth embodiment of ashadow box.

FIG. 5A is a cross-sectional view of a corner of a fifth embodiment of ashadow box.

FIG. 5B is a cross-sectional view of a corner of a sixth embodiment of ashadow box.

FIG. 5C is a cross-sectional view of a corner of a seventh embodiment ofa shadow box.

FIG. 6A is a front elevational view of a portion of a curtain wallemploying shadow boxes.

FIG. 6B is a cross sectional view of the portion of a curtain wall shownin FIG. 6A.

FIG. 7 is a cross-sectional view of a corner of a seventh embodiment ofa shadow box.

DETAILED DESCRIPTION OF THE INVENTION

A preferred embodiment of the invention is now described in detail.Referring to the drawings, like numbers indicate like parts throughoutthe views. Unless otherwise specifically indicated in the disclosurethat follows, the drawings are not necessarily drawn to scale. As usedin the description herein and throughout the claims, the following termstake the meanings explicitly associated herein, unless the contextclearly dictates otherwise: the meaning of “a,” “an,” and “the” includesplural reference, the meaning of “in” includes “in” and “on.”

As shown in FIGS. 1A and 1B, one embodiment of a prefabricated shadowbox 100 includes a vision glass panel 110 that is spaced apart from aback structure 120 so as to define a void 112 therebetween. The void 112could include air, or it could include an inert gas (such as argon orkrypton) to improve the thermal qualities of the shadow box 100. Thevision glass panel 110 includes an outside (#1) surface 111 and anopposite inside (#2) surface 114. The inside (#2) surface 114 of thevision glass panel 110 can include a coating to give the glass a desiredvisual or thermal effect. A metal panel 126 covers the back structure120 and can be painted, textured, or both, to give a desired visualeffect.

Spacers 130 separate the vision glass panel 110 from the back structure120, which typically would be at a distance of between 1″ and 6″. Thespacers 130 could include multiple chambers 131 in which a desiccant 133can be disposed so as to control humidity in the void 112. In onerepresentative embodiment, the spacers 130 comprise extruded nylon.

The spacers 130 are sealed to the vision glass panel 110 and to the backstructure 120 with a sealing material 132 that hermetically seals thevoid 112 from the external environment. The spacer 130 is typicallydesiccant filled to manage any moisture that may be in the void 112 as aresult of the assembly process. In one embodiment, the sealing material132 may comprise a polyisobutylene (PIB) sealant. This sealing material132 greatly minimizes moisture and gasses from entering and leaving thevoid 112 from or to the exterior of the shadow box 100.

A silicone seal 134 holds the spacers 130 and the vision glass panel 110in alignment with the back structure 120. In one embodiment, thestructural seal 134 comprises a construction grade silicone sealant.

The back structure 120 includes a metal envelope 122, which can includealuminum, with an insulation material 124 sealed therein. While theinsulation material 124 could comprise such materials as mineral wool orpolyisocyanurate, it could also include a newer low density silica-fumebased insulation material or an aerogel. The rigid structure of themetal envelope 122 protects such fragile materials sufficiently so as toprevent damage thereto during assembly. The edges and seams of the metalenvelope 122 may be sealed to provide a continuous air and vaporbarrier.

Additionally, in some embodiments, items can be placed into the void 112for specific purposes. For example, a lattice or grill can be placeagainst the back panel 126 to create a desired visual effect. Longlifetime LED lights could be placed into the void 112 for the purpose ofcreating visual effects at night. Light collectors, heat recovery panelsand solar energy panels could also be coupled to the back panel 126 toharvest solar energy. Generally, to place an item inside the void 112,it should be of a type that has a working lifespan that is equal to theprojected lifespan of the building because repair or replacement wouldbe quite difficult once the shadow box 100 has been installed.

In an alternative embodiment of a shadow box 200, as shown in FIG. 2,the metal panel 226 that covers the back structure 120 can include anangled surface 228 so as not to form a definite corner. Use of an angledsurface 228 can increase the perception of depth.

In another alternate embodiment, as shown in FIG. 3, the back structurecan include a second layer of glass 310 to give the shadow box 300 amore window-like appearance. A flood coat frit 312 can be applied to theback (#4) surface to give the glazing 310 a desired effect. The spacer130 cover 326 could be a painted metal sheet or a paint coating applieddirectly to the spacer 130.

In another alternate embodiment of a shadow box 400, as shown in FIG. 4,the back structure 420 can be offset to define an open area toaccommodate the placement within certain mullion configurations.Similarly, another embodiment of a shadow box 500, as shown in FIG. 5A,can include an extended exterior glazing 510 and an exterior spacer 512for use with certain existing frames. As will be well understood bythose of skill in the art, many combinations of these configurations,and many other configurations are possible without departing from thescope of the invention. As shown in FIG. 5B, if the spacer 130 has adesired aesthetic effect, then it can be left uncovered within the void112.

As shown in FIG. 5C, the exterior glazing 510 can be extended further toaccommodate the spacing of an existing curtain wall mullion system(which could include, for example, metal mullion elements 514 and seals516). Such an embodiment would include an insulation member 512 to fillin the space between the shadow box system 500 and the mullion elements514. The insulation member 512 could include a block of an insulatingmaterial such as an aerogel, or one of the many other types ofinsulating materials commonly known in the construction arts.

As shown in FIGS. 6A and 6B, a curtain wall 600 can be formed from aplurality of vision glazing panels 610 and shadow box units 100 a-c.(For simplicity, the mullions are not shown explicitly in this drawing.)As can be seen, horizontal shadow boxes 100 a can be used to hidesubfloor structures 10. Vertical shadow boxes 100 b can be used to hidecolumns 12. Several shadow boxes 100 c can be placed next to each otherto hide other areas (such as data centers or utility rooms). Thus, areasare hidden while still presenting a glazed exterior appearance. Inaddition, this shadow box can be used in any location on a buildingenclosure system, including curtain walls, where solid non-transparentpanels are desired.

As shown in FIG. 7, the shadow box 700 can include a triple-glazedsystem, in which the vision glass panel 710 can include a first visionglass pane 714 and a second glass pane 712 that are separated by aspacer 716. The spacer 716 is hermetically sealed with a sealingmaterial 720 and supported by a structural sealant 722. A back panel 730could include a third glass pane to which is applied a ceramic frit 732.

The above described embodiment of a panelized shadow box addresses thepotential technical and visual deficiencies of current state of the artshadow box construction as it provides a deep hermetically sealed shadowbox cavity constructed using processes and materials as used in themanufacture of insulating glass units.

The above described embodiment of a panelized shadow box minimizes siteinstallation works as all of the components of a shadow box arepreassembled into a panel. The minimization of installation time canlead to reduced site labor costs and increased speed of construction.

The described embodiments of a panelized shadow box improves shadow boxquality as the shadow box panel is fabricated under factory conditionswhere better quality control than ad hoc site installation is possible.The improvement in shadow box quality offers the additional advantagesof reducing ongoing maintenance costs and extending the service life ofthe shadow box.

The above described embodiments, while including the preferredembodiment and the best mode of the invention known to the inventor atthe time of filing, are given as illustrative examples only. It will bereadily appreciated that many deviations may be made from the specificembodiments disclosed in this specification without departing from thespirit and scope of the invention. Accordingly, the scope of theinvention is to be determined by the claims below rather than beinglimited to the specifically described embodiments above.

What is claimed is:
 1. A method of supplying an element for covering anon-vision area in a curtain wall on an architectural structure,comprising the steps of: (a) at a location remote from both a unitizedcurtain wall assembly shop and the architectural structure,prefabricating a plurality of shadow boxes by performing the followingsteps to assemble each of the plurality of shadow boxes: (i) sealing,with a first airtight and moisture resistant hermetic seal and a secondairtight and moisture resistant hermetic seal, an interior spacerbetween a vision glass panel and a back structure, the spacer having alength so that the vision glass panel is spaced apart from the backstructure, the back structure including a first insulating material anda rigid envelope disposed around the first insulating material andsealing the first insulating material therein, the spacer disposed alonga peripheral edge of the vision glass panel and along a peripheral edgeof the back structure so as to hold the vision glass panel in a spacedapart relationship from the back structure, so that the first hermeticseal seals the interior spacer to the vision glass panel and so that thesecond hermetic seal seals the interior spacer to the back structure andso that the vision glass panel, the back structure and the interiorspacer define a hermetically sealed void therein, wherein the firsthermetic seal and the second hermetic seal comprise polyisobutylene; and(ii) applying a structural seal about the interior spacer and so as tobe affixed to the peripheral edge of the vision glass, the interiorspacer and the back structure; and (b) delivering the plurality ofshadow boxes, after being prefabricated, to a selected one of theunitized curtain wall assembly shop and the architectural site, whereinthe back structure includes a central portion and further comprising thestep of bending a peripheral portion that extends outwardly from thecentral portion.
 2. The method of claim 1, further comprising the stepof placing at least one of the plurality of shadow boxes into apre-assembled frame structure at the selected one of the unitizedcurtain wall assembly shop and the architectural site.
 3. The method ofclaim 1, further comprising the steps of: (a) defining a plurality ofchambers in the spacer; and (b) placing a desiccant in each of theplurality of chambers.
 4. The method of claim 1, wherein the spacer hasa dimension that is selected to maintain the vision glass panel spacedapart from the back structure by at least one inch.
 5. The method ofclaim 1, wherein the first insulating material is selected from a groupof insulating materials consisting of: a mineral wool, apolyisocyanurate, a vacuum sealed fumed silica, and an aerogel.
 6. Themethod of claim 1, wherein the vision glass panel comprises at least twospaced-apart glass panes.
 7. The method of claim 1, wherein the backstructure comprises a back glass layer having an interior surface and aback surface, an further comprising the step of applying a flood coatfrit to a selected one of the interior surface and the back surface. 8.A method of supplying an element for covering a non-vision area in acurtain wall on an architectural structure, comprising the steps of: (a)at a location remote from both a unitized curtain wall assembly shop andthe architectural structure, prefabricating a plurality of shadow boxesby performing the following steps to assemble each of the plurality ofshadow boxes: (i) sealing, with a first airtight and moisture resistanthermetic seal and a second airtight and moisture resistant hermeticseal, an interior spacer between a vision glass panel and a backstructure, the spacer having a length so that the vision glass panel isspaced apart from the back structure, the back structure including afirst insulating material and a rigid envelope disposed around the firstinsulating material, the spacer disposed along a peripheral edge of thevision glass panel and along a peripheral edge of the back structure soas to hold the vision glass panel in a spaced apart relationship fromthe back structure, so that the first hermetic seal seals the interiorspacer to the vision glass panel and so that the second hermetic sealseals the interior spacer to the back structure and so that the visionglass panel, the back structure and the interior spacer define ahermetically sealed void therein; and (ii) applying a structural sealabout the interior spacer and so as to be affixed to the peripheral edgeof the vision glass, the interior spacer and the back structure; and (b)delivering the plurality of shadow boxes, after being prefabricated, toa selected one of the unitized curtain wall assembly shop and thearchitectural site, wherein the back structure includes a centralportion and further comprising the step of bending a peripheral portionthat extends outwardly from the central portion.
 9. The method of claim8, further comprising the step of placing at least one of the pluralityof shadow boxes into a pre-assembled frame structure at the selected oneof the unitized curtain wall assembly shop and the architectural site.10. The method of claim 8, further comprising the steps of: (a) defininga plurality of chambers in the spacer; and (b) placing a desiccant ineach of the plurality of chambers.
 11. The method of claim 8, whereinthe spacer had a dimension that is selected to maintain the vision glasspanel spaced apart from the back structure by at least one inch.
 12. Themethod of claim 8, wherein the first hermetic seal and the secondhermetic seal comprise polyisobutylene.
 13. The method of claim 8,wherein the first insulating material is selected from a group ofinsulating materials consisting of: a mineral wool, a polyisocyanurate,a vacuum sealed fumed silica, and an aerogel.
 14. The method of claim 8,wherein the vision glass panel comprises at least two spaced-apart glasspanes.
 15. The method of claim 8, wherein the back structure comprises aback glass layer having an interior surface and a back surface, anfurther comprising the step of applying a flood coat frit to a selectedone of the interior surface and the back surface.